VMWare ESXi upgrade

Requirements

ESXi ISO

Download the ISO from the official website. Product's name is VMware vSphere Hypervisor, file is described as ESXi ISO image.Here's where I found it in VMWare's website maze : https://my.vmware.com/group/vmware/evalcenter?p=free-esxi6. I had a license, maybe that can be downloaded for a free trial.

Create a live USB stick with it. I used gnome-multi-writer because you can't have a simpler GUI that just works... and Ubuntu's default software for Live USB, usb-creator-gtk didn't worked at the time.